USB2: ugd round bug? including patch to solve.

Daichi GOTO daichi at ongs.co.jp
Thu Jan 22 03:52:12 PST 2009


Hi USB2 folks ;-)

First I should show you my big respect. Thank you very much for your
great usb2 work. That works very well.

Using usb2, I have found a issue around uhid.  ugd will be zero-cleared
when ioctl(fd, USB_GET_REPORT_DESC, &ugd) is called.

For example, follow ioctl are used to get information of report descriptor.

     memset(&ugd, 0, sizeof(ugd));
     ugd.ugd_data = malloc(len);
     ugd.ugd_maxlen = len;

     ioctl(fd, USB_GET_REPORT_DESC, &ugd)

The information of report descriptor should be copied to ugd, but ugd is
zero-cleared.

 From my research, perphaps follow patch is good solution to solve this
problem. How do you usb2 guys make of this?  Please check and solve
this issue. Thanks :)


--- sys/dev/usb2/include/usb2_ioctl.h.orig      2009-01-22 20:11:13.000000000 +0900
+++ sys/dev/usb2/include/usb2_ioctl.h   2009-01-22 20:09:35.000000000 +0900
@@ -223,7 +223,7 @@
  #define        USB_DEVICEENUMERATE     _IOW ('U', 6, int)

  /* Generic HID device */
-#define        USB_GET_REPORT_DESC     _IOR ('U', 21, struct usb2_gen_descriptor)
+#define        USB_GET_REPORT_DESC     _IOWR('U', 21, struct usb2_gen_descriptor)
  #define        USB_SET_IMMED           _IOW ('U', 22, int)
  #define        USB_GET_REPORT          _IOWR('U', 23, struct usb2_gen_descriptor)
  #define        USB_SET_REPORT          _IOW ('U', 24, struct usb2_gen_descriptor)


-- 
   Daichi GOTO, http://people.freebsd.org/~daichi


More information about the freebsd-current mailing list